The first hypothesis-that macromutations occur in large numbers, making
the emergence of new species possible-conflicts with known facts of genetics.
One rule, put forward by R. A. Fisher, one of the last century's best known
geneticists, and based on observations, clearly invalidates this hypothesis.
Fisher states in his book The
Genetical Theory of Natural Selection that the likelihood that a particular
mutation will become fixed in a population is inversely proportional to its
effect on the phenotype. Or, to put it
another way, the bigger the mutation, the less chance it has of becoming a
permanent trait within the group.It is not hard to see the reason for this.
Mutations, as we have seen in earlier chapters, consist of chance changes in
genetic codes, and never have a beneficial influence on organisms' genetic data.
Quite the contrary: individuals affected by mutation undergo serious illnesses
and deformities. For this reason, the more an individual is affected by
mutation, the less chance it has of surviving. Ernst Mayr, the doyen of
Darwinism, makes this comment on the subject:
The occurrence of genetic monstrosities by mutation … is well
substantiated, but they are such evident freaks that these monsters can be
designated only as 'hopeless'. They are so utterly unbalanced that they would
not have the slightest chance of escaping elimination through stabilizing
selection … the more drastically a mutation affects the phenotype, the more
likely it is to reduce fitness. To believe that such a drastic mutation would
produce a viable new type, capable of occupying a new adaptive zone, is
equivalent to believing in miracles … The finding of a suitable mate for the
'hopeless monster' and the establishment of reproductive isolation from the
normal members of the parental population seem to me insurmountable
difficulties.
It is obvious that mutations cannot bring about evolutionary development,
and this fact places both neo-Darwinism and the punctuated equilibrium theory of
evolution in a terrible difficulty. Since mutation is a destructive mechanism,
the macromutations that proponents of the punctuated equilibrium theory talk
about must have "macro" destructive effects. Some evolutionists place their
hopes in mutations in the regulatory genes in DNA. But the feature of
destructiveness which applies to other mutations, applies to these, as well. The
problem is that mutation is a random change: any kind of random change in a
structure as complex as genetic data will lead to harmful
results.
![]() Two famous proponents of the punctuated evolution model: Stephen Jay Gould and Niles Eldredge. |
In their book The Natural
Limits to Biological Change, the geneticist Lane Lester and the population
biologist Raymond Bohlin describe the blind alley represented by the notion of
macromutation:
The overall factor that has come up again and again is that mutation remains the ultimate source of all genetic variation in any evolutionary model. Being unsatisfied with the prospects of accumulating small point mutations, many are turning to macromutations to explain the origin of evolutionary novelties. Goldschmidt's hopeful monsters have indeed returned. However, though macromutations of many varieties produce drastic changes, the vast majority will be incapable of survival, let alone show the marks of increasing complexity. If structural gene mutations are inadequate because of their inability to produce significant enough changes, then regulatory and developmental mutations appear even less useful because of the greater likelihood of nonadaptive or even destructive consequences… But one thing seems certain: at present, the thesis that mutations, whether great or small, are capable of producing limitless biological change is more an article of faith than fact.
Observation and experiment both show that mutations do not enhance
genetic data, but rather damage living things. Therefore, it is clearly
irrational for proponents of the punctuated equilibrium theory to expect greater
success from "mutations" than the mainstream neo-Darwinists have
found. Darwinism
Refuted.
